In the final year of the project, we intend to carry out experiments on 1) forward masking in impaired listeners, 2) the relation between gap detection and forward masking, 3) measurement of simultaneous masking through lateralization, and 4) pitch shifts as a function of intensity and pitch shifts under partial masking. Studies of forward masking in impaired listeners will attempt to separate growth of masking from decay of masking, to determine which process is abnormal. The study of gap detection and forward masking will concentrate on the relation between these processes when the masker and signal or the gap markers differ in frequency. The lateralization experiments are intended to give us more complete data on partial masking. In the pitch shift experiments, we will be concerned with developing a stable measure of pitch shifts as a function of intensity, in quiet and under partial-masking conditions.